why the hell do I keep essaying
...Right, so.
Dominance in Okita's Social Interactions.
No, I don't mean it that way. You know who you are, stop thinking that. >_>
Okita is actually an extremely dominant person in most of his interactions, to the point of being a bit of a control freak. The closer he considers you, the less likely he is to exercise control of the conversation. If he actually feels threatened or attacked verbally -- for instance, if you say something that really gets to him without his giving permission, which has happened so far with Count D and Watanuki -- he'll be much more careful to remain in control in the future.
Trying to control the conversation or situation when Okita's actually fighting you for control of it will make him extremely uncomfortable and probably also make him very angry with you. Extremely close friends or people who he sees as legitimately dominant to him get a pass on that one; he'll be uncomfortable but will express it as withdrawal instead of anger.
Okita's interactions with people who he sees as socially his superior tend to be more playful and much less controlling. He'll avoid giving direct orders, tease more often, accept criticism or assertions of dominance (orders, blatant topic changes, et cetera) without question, and often act more childish.
The ways to register with Okita as his legitimate social superior are: be a nobleman and act like it (he'll treat you with polite deference and probably impeccable manners); be his sempai in the Shinsengumi (he'll treat you very playfully, also you get automatic backup if you need it, Edo Shinsengumi do not count); or beat him soundly in a sparring match and be friendly about it.
Okita is probably at his most relaxed in friendly conversation with someone he sees as a social superior, because in that situation he doesn't care about maintaining his dignity or his control of the conversation; he gives control over to the other person, as their right. Second most relaxed would be friendly conversation with someone he sees as a social inferior, where he is in control of the conversation. The least relaxed he'll be in a social situation is during a serious conversation with a social inferior who is trying to take control of the conversation.
Marks of dominance in a conversation from Okita's perspective are, in order of strength from weakest to strongest: changing the topic, giving a suggestion, asking a direct question, giving an order. If he asks direct questions or gives orders to someone who ranks as his superior, then either he's angry, the situation is very serious and he thinks he knows best, or he's being extremely playful. Check the icon.
Marks of submission in a conversation are, in order of strength: following a subject change without giving you trouble about it (trouble includes laughing at you or knowing looks), answering a direct question directly with no fudging or talking around the topic, accepting a suggestion or order briefly ("Yes," or "Thank you for your [help/advice]," et cetera), asking for help or advice, offering his help openly. Yes, asking for help or advice is a very submissive thing to do, from Okita's perspective, which is one of the reasons he doesn't like doing it. It hurts his pride, particularly if he's asking for help from someone who he sees as an equal or inferior. I also note that if he just helps you without asking your permission first, that's actually a mark of dominance, not submission: it's "I know better than you do, and I'm going to deal with this situation for you." Asking if you want his help, though, is both an admission that you know better than he does and an invitation for you to give him an order, and thereby pretty much his strongest expression of submission. Also, giving information in detail when someone asks for it is more a dominant/teacher thing than a submissive one; it's when he gives information briefly and/or answers with Yes or No that he's answering a direct question submissively (particularly if he's visibly uncomfortable with the topic.)
I also should note that Okita doesn't think less of you if he thinks of you as an inferior. I'm using the term in the sense of "less dominant (目下)" not in the sense of "lesser." There are quite a few people whom he's very close to and holds in high esteem and still thinks of as a social inferior.
Okita would rank his friends, in terms of dominance, in the following manner:
Saitou (sempai in the Shinsengumi, equal or superior swordsman, older man who uses familiar Japanese high-social-dominance signals; Okita falls naturally into a sempai-kouhai relationship with Saitou.)
Wolfram (equal/very slightly inferior, older man who looks and in most situations acts younger, someone to whom Okita's given advice and from whom Okita accepts advice and help. Okita'd actually like to spar with Wolfram in part to work out which of them actually is better, because "equal" is kind of a weird and uncomfortable place for him to be with someone.)
Naoto (younger woman, but not too much younger; good with a sword, definitely competent on her own; she really reminds Okita a lot of himself when he was a bit younger, and as such rates as inferior/independent. He wouldn't give orders or advice to her outside of the teacher/student relationship unless she requested them, but he won't be submissive around her, either.)
Yukina (younger woman, has her own very valuable skill set and Okita's accepted help from her quite a few times; he sees her as a definite social inferior and therefore someone who he'd automatically help or defend without asking, but not someone to whom he'd freely give orders.)
Senri (younger man, student, still largely helpless in Okita's opinion. Okita sees himself as not just dominant to but actually responsible for Senri, and will freely give orders, reprimand when necessary, explain things, and keep information from Senri if he feels it's necessary.)
...and anyone else who I didn't list (that's definitely not exhaustive), please feel free to comment and ask where you rank.